Physical and Mechanical Properties of Zr-Based Metallic Glasses

Abstract

Thermal properties, oxidation, hardness, thermal expanstion, electric resistance and Young's modulus were examined for Zr 67 Cu 33 , Zr 65 Al 7.5 Cu 27.5 , Zr 65 Al 7.5 Ni 10 Cu 17.5 and Zr 60 Al 15 Co 2.5 Ni 7.5 Cu 15 amorphous alloys with a wide supercooled liquid region. The results show that (1) Zr 65 Al 17.5 Ni 10 Cu 17.5 and Zr 60 Al 15 Co 2.5 Ni 7.5 Cu 15 alloys are very stable against oxidation up to high temperature of about 650 K, (2) Zr 60 Al 15 Co 2.5 Ni 7.5 Cu 15 alloy is extremely softened in the temperature range of the supercooled liquid region, (3) The thermal expansion coefficient of Zr 60 Al 15 Co 2.5 Ni 7.5 Cu 15 alloy is very small of 0.9 x 10 -5 K -1 , at temperatures below the glass transition temperature (T g ), (4) Temperature coefficient of electric resistance of Zr 60 Al 15 Co 2.5 Ni 7.5 Cu 15 alloy is small of -9 x10 -5 K -1 below about 510 K and (5) Young's modulus increases with increase of alloying components. The temperature dependance of Young's modulus is of the order of as small as ∼10 -5 K -1 except for Zr 67 Cu 33 alloys.